One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,5,7,8)(9,10)(11,16)(12,17)(13,18)(14,15)(19,24)(20,23)(21,22)(25,26,30,31)(27,28,33,32)(29,37,38,34)(35,39,40,36)(3,7)(5,8)(10,15)(12,22)(16,24)(18,20)(25,27)(26,28)(29,35)(30,33)(31,32)(34,36)(37,39)(38,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(11,19)(13,23)(16,24)(18,20)(26,31)(27,33)(29,38)(36,39) involution — undirected(9,11,14,19)(10,16,15,24)(12,18,22,20)(13,21,23,17)(25,27)(26,32)(28,31)(29,35)(30,33)(34,39)(36,37)(38,40)(1,3)(2,5)(4,7)(6,8)(9,12,14,22)(10,17,15,21)(11,20,19,18)(13,16,23,24)(25,28,30,32)(26,33,31,27)(29,36,38,39)(34,40,37,35)(1,2)(3,5)(4,6)(7,8)(9,13,14,23)(10,18,15,20)(11,21,19,17)(12,16,22,24)(25,29)(26,34)(27,35)(28,36)(30,38)(31,37)(32,39)(33,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.